Suspension assembly and disk device

ABSTRACT

According to one embodiment, a suspension assembly includes a support plate, a wiring member disposed on the support plate, and a head supported on the support plate through the wiring member. The wiring member includes a distal end portion electrically connected to the head, a connection end portion extending outside the support plate, and a plurality of wirings extending between the distal end portion and the connection end portion. The connection end portion includes an opening with predetermined length and width and thirteen or more connection terminals disposed in the opening and arranged at intervals in a direction of the length. A percentage of an area of the opening occupied by areas of the thirteen or more connection terminals is 40% to 65% inclusive.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromJapanese Patent Application No. 2020-038797, filed Mar. 6, 2020, theentire contents of which are incorporated herein by reference.

FIELD

Embodiments described herein relate generally to a suspension assemblyused for a disk device and a disk device including the suspensionassembly.

BACKGROUND

A magnetic disk device as an example of the disk device includesmagnetic disks disposed in a base, a spindle motor that supports androtates the magnetic disks, and a head actuator, in general. The headactuator comprises a plurality of suspension assemblies respectivelysupporting magnetic heads. Each of the suspension assemblies includes asuspension mounted to a distal end portion of an arm of the headactuator and a wiring member (a flexure, a wiring trace) disposed on thesuspension. A magnetic head is supported on a gimbal portion of thewiring member to thereby form a head suspension assembly. A plurality ofconnection terminals are provided at a connection end portion of thewiring member. The connection terminals are electrically connected tothe magnetic head via wirings of the wiring member. The connection endportion is solder-joined to a connection pad of a flexible printedcircuit board (FPC) provided on an actuator block.

In order to achieve higher density and higher reliability of recentmagnetic disk devices, addition of a head disk interface (HDI) sensor, amulti-stage actuator, a dynamic flight height (DFH) control function,and a high frequency assisted recording or heat assisted recordingfunction to each of heads or each of suspension assemblies is beingconsidered. For this purpose, the number of the connection terminalsprovided at the connection end portion of each of the wiring membersneeds to be further increased.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of a hard disk drive (HDD)according to a first embodiment.

FIG. 2 is a perspective view of an actuator assembly and a board unit(FPC unit) of the HDD.

FIG. 3 is a perspective view of a suspension assembly of the actuatorassembly.

FIG. 4 is a side view of an actuator block, a joint portion (FPC jointportion) of the FPC unit, and tail connection end portions of flexuresof the actuator assembly.

FIG. 5 is a front view of the joint portion of the FPC unit.

FIG. 6 is a sectional view of the flexure.

FIG. 7 is a plan view of the tail connection end portion of the flexure.

FIG. 8 is a graph for comparing relationships between a laser output, anirradiation time, and a joined state in solder-joining the tailconnection end portion (without a heat insulation layer) with those in acomparative example.

FIG. 9 is a graph for comparing relationships between a laser output, anirradiation time, and a joined state in solder-joining the tailconnection end portion (with the heat insulation layer) with those in acomparative example.

FIG. 10 is an enlarged plan view of a tail connection end portion of aflexure according to a second embodiment.

FIG. 11A is a schematic plan view of a tail connection end portion of aflexure according to a third embodiment.

FIG. 11B is a schematic plan view of a tail connection end portion of aflexure according to a fourth embodiment.

FIG. 12A is a schematic plan view of a tail connection end portion of aflexure according to a fifth embodiment.

FIG. 12B is a schematic plan view of a tail connection end portion of aflexure according to a sixth embodiment.

DETAILED DESCRIPTION

Various embodiments will be described hereinafter with reference to theaccompanying drawings. In general, according to one embodiment, asuspension assembly comprises a support plate; a wiring member disposedon the support plate; and a head supported on the support plate throughthe wiring member. The wiring member comprises a distal end portionelectrically connected to the head, a connection end portion extendingoutside the support plate, and a plurality of wirings extending betweenthe distal end portion and the connection end portion. The connectionend portion includes an opening with predetermined length and width andincludes thirteen or more connection terminals disposed in the openingand arranged at intervals in a direction of the length. A percentage ofan area of the opening occupied by the sum of areas of the thirteen ormore connection terminals is 40% to 65% inclusive.

The disclosure is merely an example and changes made appropriatelywithout departing from the spirit of the invention and a person skilledin the art can easily conceive of are naturally included in the scope ofthe present invention. Although the drawings are schematicrepresentations of actual modes in some cases with regard to widths,thicknesses, shapes, and the like of respective portions for the sake ofclearer explanation, the drawings merely illustrate examples and are notintended to limit interpretation of the present invention. In thepresent description and the respective figures, components similar tothose described already in relation to the already-mentioned drawingswill be provided with the same reference signs and will not be describedin detail as appropriate in some cases.

First Embodiment

As a disk device, a hard disk drive (HDD) according to the firstembodiment will be described in detail.

FIG. 1 is an exploded perspective view of the HDD according to the firstembodiment with a detached top cover.

The HDD comprises a housing 10 in a flat and substantially rectangularshape. The housing 10 comprises a base 12 in a shape of an open-toprectangular box and a top cover 14. The base 12 comprises a bottom wall12 a in a rectangular shape and facing the top cover 14 with a clearancefrom the top cover 14, and a plurality of side walls 12 b standing alonga peripheral edge of the bottom wall, and the base 12 is integrallymolded of aluminum, for example. The top cover 14 is formed in arectangular plate shape by use of stainless steel, for example. The topcover 14 is fixed to tops of the side walls 12 b of the base 12 by useof a plurality of screws 13 to close a top opening of the base 12.

In the housing 10 are provided a plurality of magnetic disks 18 asrecording media and a spindle motor 19 as a drive unit that supports androtates the magnetic disks 18. The spindle motor 19 is disposed on thebottom wall 12 a. Each of the magnetic disks 18 is 3.5 inches, forexample, and includes a magnetic recording layer on an upper face and/ora lower face. The respective magnetic disks 18 are coaxially fitted witha hub (not shown) of the spindle motor 19 and fixed to the hub byclamping with a clamp spring 20. The respective magnetic disks 18 aresupported in such positions as to be parallel to the bottom wall 12 a ofthe base 12. The plurality of magnetic disks 18 are rotated at apredetermined rotation speed by the spindle motor 19. Although the fivemagnetic disks 18, for example, are housed in the housing 10 in thepresent embodiment, the number of the magnetic disks 18 is not limitedto five.

In the housing 10 are provided a plurality of magnetic heads 17 thatcarry out recording and reading of information on and from the magneticdisks 18 and an actuator assembly (carriage assembly) 22 which supportsthe magnetic heads 17 to be movable with respect to the magnetic disks18. In the housing 10, a voice coil motor (hereinafter referred to as“VCM”) 24 that rotates and positions the actuator assembly 22, a rampload mechanism 25 that retains the magnetic heads 17 in unload positionsseparate from the magnetic disks 18 when the magnetic heads 17 move tooutermost peripheries of the magnetic disks 18, and a board unit (FPCunit) 21 mounted with electronic components such as a conversionconnector are provided.

The actuator assembly 22 comprises an actuator block 29 supported by abearing unit 28 to be rotatable about a support shaft 26, a plurality ofarms 32 extending from the actuator block 29, and suspension assemblies30 extending from the respective arms 32. The magnetic heads 17 aresupported on distal end portions of the respective suspension assemblies30. The support shaft 26 stands on the bottom wall 12 a. Each of themagnetic heads 17 includes a read head, a write head, an assistingelement, a heater, and the like.

To an outer face of the bottom wall 12 a of the base 12, a printedcircuit board (not shown) is fixed by screws. The printed circuit boardforms a control unit that controls operation of the spindle motor 19 andoperation of the VCM 24 and the magnetic heads 17 via the board unit 21.

FIG. 2 is a perspective view of the actuator assembly and the FPC unitand FIG. 3 is a perspective view of the suspension assembly. As shown inFIG. 2, the actuator assembly 22 includes the actuator block 29 having athrough hole 31, the bearing unit (unit bearing) 28 provided in thethrough hole 31, the plurality of (e.g., six) arms 32 extending from theactuator block 29, the suspension assemblies 30 mounted to therespective arms 32, and the magnetic heads 17 supported on thesuspension assemblies 30. The actuator block 29 is supported by thebearing unit 28 to be rotatable about the support shaft (pivot) 26standing on the bottom wall 12 a.

In the present embodiment, the actuator block 29 and the six arms 32 areintegrally molded of aluminum or the like to form what is called“E-block”. The arms 32 are formed in long and narrow flat plate shapes,for example, and extend from the actuator block 29 in a directionperpendicular to the support shaft 26. The six arms 32 are arranged atintervals to be parallel to each other.

The actuator assembly 22 has a support frame 36 extending from theactuator block 29 in an opposite direction from the arms 32 and thesupport frame 36 supports a voice coil 34 that forms a part of the VCM24. As shown in FIG. 1, the voice coil 34 is positioned between pairedyokes 38, one of which is fixed onto the base 12, and forms the VCM 24with the yokes 38 and a magnet fixed to one of the yokes.

The actuator assembly 22 comprises the ten suspension assemblies 30 thatrespectively support the magnetic heads 17 and the suspension assemblies30 are respectively mounted to distal end portions 32 a of therespective arms 32. The plurality of suspension assemblies 30 includeup-head suspension assemblies that support the magnetic heads 17 face upand down-head suspension assemblies that support the magnetic heads 17face down. The up-head suspension assemblies and the down-headsuspension assemblies are formed by arranging the suspension assemblies30 with the same structures while changing vertical orientations of thesuspension assemblies 30.

In the present embodiment, in FIG. 2, the down-head suspension assembly30 is mounted to the uppermost arm 32 and the up-head suspensionassembly 30 is mounted to the lowermost arm 32. To the four middle arms32, the up-head suspension assemblies 30 and the down-head suspensionassemblies 30 are mounted, respectively.

As shown in FIG. 3, the suspension assembly 30 comprises a base plate 44in a substantially rectangular shape, a load beam 46 in a shape of along and narrow leaf spring, and a flexure (wiring member) 48 in a longand narrow band shape. A proximal end portion of the load beam 46 isoverlaid on and fixed to an end portion of the base plate 44. The loadbeam 46 extends from the base plate 44 and tapers toward an extendedend. The base plate 44 and the load beam 46 are made of stainless steel,for example.

The base plate 44 has, in a proximal end portion thereof, a circularopening and an annular protruding portion 51 positioned at a peripheryof the opening. The base plate 44 is fastened to the distal end portion32 a of the arm 32 by fitting the protruding portion 51 of the baseplate 44 in a crimp hole 40 formed in the distal end portion 32 a of thearm 32 and crimping the protruding portion 51 (see FIG. 2). The proximalend portion of the load beam 46 is overlaid on the distal end portion ofthe base plate 44 and fixed to the base plate 44 by welding at aplurality of positions.

The flexure 48 of the suspension assembly 30 is a layered plate in along and narrow band shape and having a metal plate (backing layer) madeof stainless steel or the like and serving as a base and a flexibleprinted circuit board (FPC) disposed on the metal plate.

The flexure 48 has a distal end side portion 48 a and a proximal endside portion 48 b. The distal end side portion 48 a is mounted to theload beam 46 and the base plate 44. The proximal end side portion 48 bextends outward from a side edge of the base plate 44 and furtherextends along the arm 32 to a proximal end portion (the actuator block29) of the arm 32.

The flexure 48 has a distal end portion positioned on the load beam 46and a gimbal portion (resilient support portion) 52 that is formed atthe distal end portion and can be displaced. The magnetic head 17 ismounted to the gimbal portion 52. Paired piezoelectric elements 53forming micro-actuators are mounted to the gimbal portion 52 anddisposed on opposite sides of the magnetic head 17. The distal endportion of the flexure 48 is electrically connected to the read headelement, the write head element, the heater, the assisting element, anHDI sensor, and other members of the magnetic head 17 and thepiezoelectric elements 53 via wirings and connection pads (not shown).

The flexure 48 includes the connection end portion (tail connectionterminal portion) 48 c provided to one end of the proximal end sideportion 48 b. The connection end portion 48 c is formed in a long andnarrow rectangular shape. The connection end portion 48 c is bent at asubstantially right angle to the proximal end side portion 48 b to bepositioned substantially perpendicularly to the arm 32. The plurality of(e.g., thirteen) connection terminals (connection pads) 50 are providedto the connection end portion 48 c. The connection terminals 50 arerespectively connected to the wirings of the flexure 48. In other words,the plurality of wirings of the flexure 48 extend throughout an almostentire length of the flexure 48 and are electrically connected at oneends to the magnetic head 17 and connected at the other ends to theconnection terminals (connection pads) 50 of the connection end portion48 c.

As shown in FIG. 2, the ten suspension assemblies 30 extend from the sixarms 32 and are arranged substantially parallel at predeterminedintervals to face each other. The suspension assemblies 30 form the fivedown-head suspension assemblies and the five up-head suspensionassemblies. The down-head suspension assembly 30 and the up-headsuspension assembly 30 in each pair are positioned parallel with apredetermined clearance left therebetween and the magnetic heads 17 arepositioned to face each other. The magnetic heads 17 are positioned toface opposite faces of the corresponding magnetic disk 18.

As shown in FIG. 2, the FPC unit 21 integrally has a base portion 60 ina substantially rectangular shape, a relay portion 62 in a long andnarrow band shape and extending from one side edge of the base portion60, and a joint portion (FPC joint portion) 64 in a substantiallyrectangular shape and provided continuously with a distal end portion ofthe relay portion 62. The base portion 60, the relay portion 62, and thejoint portion 64 are formed by flexible printed circuit boards (FPCs).

On one of surfaces (an outer face) of the base portion 60, theelectronic components such as the conversion connector (not shown) and aplurality of capacitors 63 are mounted and electrically connected towirings (not shown). To the other surfaces (inner faces) of the baseportion 60, two metal plates 70, 71 that serve as reinforcing plates arerespectively bonded. The base portion 60 is disposed on the bottom wall12 a of the housing 10 and fixed to the bottom wall 12 a by use of twoscrews. The conversion connector on the base portion 60 is connected tothe control circuit board provided on the bottom face side of thehousing 10.

The relay portion 62 extends from the base portion 60 toward theactuator assembly 22. The joint portion 64 provided to an extended endof the relay portion 62 is formed in the rectangular shape havingsubstantially equal height and width to a side face (mounting face) ofthe actuator block 29. The joint portion 64 is bonded to the mountingface of the actuator block 29, with a backing plate made of aluminum orthe like interposed therebetween, and fixed to the mounting face by useof fixing screws.

The connection end portions 48 c of the ten flexures 48 are joined to aplurality of connection portions of the joint portion 64 andelectrically connected to wirings of the joint portion 64. The pluralityof connection end portions 48 c are arranged in a direction parallel tothe support shaft 26. A head IC (head amplifier) 54 is mounted on thejoint portion 64 and the head IC 54 is connected to the connection endportions 48 c and the base portion 60 by the wirings of the FPC.Furthermore, the joint portion 64 has a pair of connection pads 55 andthe voice coil 34 is connected to the connection pads 55.

The ten magnetic heads 17 of the actuator assembly 22 are electricallyconnected to the base portion 60 via the wirings of the flexures 48, theconnection end portions 48 c, the joint portion 64 of the FPC unit 21,and the relay portion 62, respectively. Moreover, the base portion 60 iselectrically connected to the printed circuit board on the bottom faceside of the housing 10 via the conversion connector.

A wiring structure of the FPC joint portion 64 will be described indetail. FIG. 4 is a side view of the joint portion 64 mounted on theactuator block and the plurality of connection end portions and FIG. 5is a side view of the joint portion 64 before the connection endportions are joined.

As shown in FIG. 5, the joint portion 64 of the FPC has ten connectionpad groups 72 corresponding to the connection end portions 48 c of thesuspension assemblies 30. Each of the connection pad groups 72 includesthirteen connection pads 73, for example, arranged in a row, and each ofthe connection pads 73 is electrically connected to the base portion 60by the wiring. The thirteen connection pads 73 of each group 72 arearranged at predetermined intervals in a direction substantiallyparallel to the arm 32. The ten connection pad groups 72 are arranged atintervals and substantially parallel to each other in the directionparallel to the support shaft 26, i.e., a height direction of theactuator block 29. The connection pads 73 are positioned in an opening76 in a band shape and formed in a cover insulating layer (describedlater) of the FPC and are exposed to an outside through the opening 76.Before the connection end portions 48 c are joined, solder layers 78 areformed on the respective connection pads 73.

As shown in FIGS. 4 and 5, the joint portion 64 of the FPC is fixed tothe mounting face of the actuator block 29 with the backing plateinterposed therebetween. The connection end portions 48 c of theflexures 48 are overlaid on the respective connection pad groups 72 ofthe joint portion 64. The connection terminals 50 of the connection endportions 48 c respectively come in contact with the correspondingconnection pads 73 with the solder layers 78 interposed therebetween. Aswill be described later, the respective connection terminals 50 of theconnection end portions 48 c are mechanically and electricallysolder-joined to the corresponding connection pads 73 by melting of thesolder layers 78 with laser irradiation.

Next, a structure of each of the flexures 48 and details of a structureof each of the connection end portions 48 c will be described.

FIG. 6 is a sectional view of a layered structure of the flexure 48 andFIG. 7 is an enlarged plan view of the connection end portion.

As shown in FIG. 6, the flexure 48 comprises a metal plate (backinglayer) 80 made of stainless steel or the like and serving as a base, anda flexible printed circuit board (FPC) 82 provided on the metal plate.In the present embodiment, a heat insulation layer 84 is providedbetween the metal plate 80 and the FPC 82. The FPC 82 is formed by amultilayered body having a base insulating layer 86 a, conductive layers86 b, 86 c respectively layered on opposite faces of the base insulatinglayer 86 a, and cover insulating layers (protective layers) 88 a, 88 boverlaid and layered on the respective conductive layers. The conductivelayers 86 b, 86 c are formed of sheets of cupper foil, for example, anda plurality of wirings, connection terminals, and connection pads areformed by patterning the copper foil. The FPC 82 is not limited to themultilayer structure. It is also possible to use an FPC having asingle-layer structure including a base insulating layer, a singleconductive layer, and cover insulating layers. The heat insulation layer84 can be omitted.

As shown in FIG. 7, the connection end portion 48 c of the flexure 48 isformed in the long and narrow substantially rectangular shape. Theconnection end portion 48 c has an opening 90 in a rectangular shape andformed in a central portion of the connection end portion. The opening90 is formed to have a longitudinal length L of 6 mm or less and a widthW of 0.5 mm, for example. The above-described thirteen connectionterminals 50 are positioned in the opening 90 and arranged at intervalsin a longitudinal direction of the opening 90. Each of the connectionterminals 50 extends from one end to the other end of the opening 90 ina width direction. The respective connection terminals 50 areelectrically connected to the connection pads at the distal end portionof the flexure 48 by the wirings S, respectively.

A width WT of the connection terminal 50 is 0.2 mm, for example. Each ofthe intervals between the connection terminals 50 is 0.15 mm or wider. Athrough hole is formed in a central portion of each of the connectionterminals 50. A percentage of an area of the opening 90 occupied by thesum of areas of all the connection terminals 50 (including the throughholes) is 40% or more, for example, 43%.

The intervals between the connection terminals 50 may be equal to eachother. In the present embodiment, however, from an extended end side ofthe connection end portion 48 c, a wider interval 90 a (of 0.3 mm, forexample) is disposed after every third connection terminal 50. The widerintervals 90 a are provided so that a jig can be disposed at the widerintervals 90 a in solder-joining of the connection terminals 50.

In the present embodiment, the thirteen connection terminals 50 arearranged in the following order in consideration of an influence ofcrosstalk. In an example, from the extended end side of the connectionend portion 48 c, the four connection terminals 50(R) for the read head,the two connection terminals 50(S) for the HDI sensor, the twoconnection terminals 50(A) for the assisting element (the high frequencyassisting element or the heat assisting element), the two connectionterminals 50(H) for the heater, the two connection terminals 50(W) forthe write head, and lastly the one connection terminal 50(G) for thegimbal micro-actuators (GMA) (piezoelectric elements 53) are arranged inthis order. In other words, the sixth and seventh connection terminals50(A) (from a proximal end side) for the assisting element are disposedat a central portion in an arranged direction, the connection terminals50(W) for the write head are disposed on the proximal end side of theconnection end portion 48 c, and the connection terminals 50(H) for theheater are provided between the connection terminals 50(A) for theassisting element and the connection terminals 50(W) for the write head.The connection terminals 50(R) for the read head are disposed on thedistal end side of the connection end portion 48 c and the connectionterminals 50(S) for the HDI sensor is provided between the connectionterminals 50(A) for the assisting element and the connection terminals50(R) for the read head.

With the above-described arrangement, it is possible to widen theinterval between the connection terminals 50(W) for the write head andthe connection terminals 50(A) for the assisting element and theinterval between the connection terminals 50(R) for the read head andthe connection terminals 50(A) for the assisting element to therebyprevent the crosstalk between the terminals in driving. By providing theconnection terminals 50(W) for the write head at the proximal endportion of the connection end portion 48 c, it is possible to minimizelengths of the wirings between the connection terminals 50(W) and themagnetic head 17, which reduces an impedance of the wiring. Thearrangement of the connection terminals 50 is not limited to theabove-described arrangement. To avoid the crosstalk, the connectionterminals 50 may be arranged such that the connection terminals for thewrite head and the connection terminals for the read head are notadjacent to the connection terminals for the assisting element.

Each of the connection end portions 48 c formed as described above isdisposed on the joint portion 64 of the FPC unit as shown in FIG. 4 andthe thirteen connection terminals 50 are overlaid on the correspondingconnection pads 73. If the respective connection terminals 50 and theconnection pads 73 are irradiated with laser, the solder layers 78printed on the connection pads 73 and the connection terminals 50directly absorb heat. As a result, insulating layers on the connectionterminals 50 and the solder layers 78 melt and the connection terminals50 and the connection pads 73 are solder-joined to each other. Thus, theconnection end portion 48 c and the joint portion 64 are electricallyand mechanically joined to each other and conductivity between theconnection end portion 48 c and the joint portion 64 is secured.

FIG. 8 is a graph for comparing relationships between a laser output, anirradiation time, and joined states in solder-joining the tailconnection end portion (without the heat insulation layer) with those ina comparative example. FIG. 9 is a graph for comparing relationshipsbetween a laser output, an irradiation time, and joined states insolder-joining the tail connection end portion (with the heat insulationlayer) with those in a comparative example. As each of the comparativeexamples, a tail connection end portion having nine connection terminalsprovided in an opening is used.

In each of the comparative examples, intervals between the nineconnection terminals are wide and a percentage of an area of the openingoccupied by the sum of areas of all the connection terminals is about35%. In this case, as shown by a one-dot chain line in FIG. 8, in thecomparative example, it is necessary to increase the laser output (anamount of heat) of the laser irradiation in order to secure a necessaryamount of heat to melt the solder. The larger amount of heat isnecessary to secure the necessary amount of heat to melt the solder. Asa result, an allowable temperature of the insulating layers (polyimide)of the connection end portion that receive the heat is exceeded and thepolyimide burns or changes in color. Therefore, in the comparativeexample, damage to the connection end portion (tail damage) causes areduction in a margin of the laser output.

On the other hand, if the heat insulation layer is provided to each ofthe flexures to suppress escape of heat from the connection end portion48 c to the joint portion 64 of the FPC, solder joining can be carriedout with a lower laser output, which reduces a risk of the tail damagein the comparative example as shown in FIG. 9, while the heat is trappedin the joint portion 64 and a temperature increase is likely to occur.Therefore, delamination becomes likely to occur between the conductivelayers and the insulating layers in vias positioned near the connectionterminals. The delamination varies depending on a moisture absorbingstate of the FPC and causes the reduction in the margin of the laseroutput.

On the other hand, by providing the thirteen connection terminals 50 inthe opening 90 at the connection end portion (tail connection endportion) 48 c according to the present embodiment, a percentage of thearea of the opening 90 occupied by the sum of areas of the connectionterminals 50 increases to 40% or higher. As a result, in melting thesolder, heat is less likely to escape and it is possible to efficientlyabsorb the heat of the laser. Without the heat insulation layer, in thecase of the connection end portion 48 c according to the presentembodiment, it is possible to reduce a minimum laser output necessaryfor the solder joining to thereby widen a margin of the laser outputbefore the tail damage is caused as shown by a solid line in FIG. 8 ascompared with the comparative example. At the same time, as comparedwith the comparative example, it is possible to widen a margin beforethe delamination is caused.

With the heat insulation layer, in the case of the connection endportion 48 c according to the present embodiment, it is possible toreduce the minimum laser output and it is possible to increase the laseroutput before the delamination is caused to thereby increase the marginof the laser output as shown by a solid line in FIG. 9 as compared withthe comparative example.

If the intervals between the connection terminals 50 are narrower thanor equal to 0.15 mm in the connection end portion 48 c, manufacture ofthe connection terminals 50 becomes difficult and a risk of a shortcircuit between the terminals increases. An example of the arrangementof the thirteen terminals with which the risk of the short circuit canbe avoided and the percentage occupied by the areas of the connectionterminals 50 can be maximized is a structure with the opening 90 havinga length L of 6 mm, intervals of 0.15 mm between the connectionterminals 50, and terminal widths WT of 0.3 mm. In this case, apercentage of an area of the opening 90 occupied by areas of theconnection terminals 50 is about 65% and therefore the areas of theconnection terminals 50 preferably occupy 65% or less of the opening 90.An example with which the risk of the short circuit can be avoided andthe number of the arranged connection terminals can be maximized is astructure in which the seventeen connection terminals 50 having terminalwidths WT of 0.2 mm are arranged at intervals of 0.15 mm in the opening90 having a length L of 6 mm. In this case, a percentage of an area ofthe opening 90 occupied by areas of the connection terminals 50 is about56%. Therefore, the areas of the connection terminals 50 preferablyoccupy 56% or less of the opening area.

As shown in FIG. 1, when the actuator assembly 22 and the FPC unit 21formed as described above are mounted into the base 12, the actuatorassembly 22 is supported to be able to turn about the support shaft 26.Each of the magnetic disks 18 is positioned between the two suspensionassemblies 30. During operation of the HDD, the magnetic heads 17mounted to each of the suspension assemblies 30 face the upper face andthe lower face of each of the magnetic disks 18, respectively. The baseportion 60 of the FPC unit 21 is fixed to the bottom wall 12 a of thebase 12.

With the HDD and the suspension assemblies formed as described above, bydisposing the thirteen connection terminals 50 in the opening 90 havingthe predetermined length L at the connection end portion 48 c of each ofthe flexures 48, the percentage of the area of the opening 90 occupiedby the areas of the connection terminals 50 is set to 40% to 65%inclusive. Thus, in solder-joining the connection terminals 50, the heatis less likely to escape and it is possible to efficiently absorb theheat of a heating unit. Therefore, it is possible to widen the margin ofthe output of the heating unit before the tail damage and thedelamination are caused to thereby carry out stable solder joiningwithout causing the tail damage and the delamination.

From the above, according to the first embodiment, it is possible toincrease the number of the connection terminals without expanding anarea in which the connection terminals are mounted and it is possible toprovide the large-capacity and high-performance magnetic disk device andthe suspension assemblies.

Next, suspension assemblies of HDDs according to the other embodimentswill be described. In the other embodiments described below, the sameportions as those in the above-described first embodiment will beprovided with the same reference signs and will not be described indetail or will be described briefly and portions different from those inthe first embodiment will be mainly described.

Second Embodiment

FIG. 10 is an enlarged plan view of a connection end portion of aflexure used for the suspension assembly according to the secondembodiment. As shown in FIG. 10, according to the second embodiment, theconnection end portion 48 c has fourteen connection terminals 50arranged in an opening 90 having a length L of about 6 mm. A width WT ofeach of the connection terminals 50 is set to 0.2 mm as in the firstembodiment. In the present embodiment, the one connection terminal 50(G)for micro-actuators (piezoelectric elements) is added. The connectionterminal 50(G) is disposed at a closest end portion of the opening 90 toa proximal end. The other thirteen connection terminals 50 are arrangedin the same way as in the first embodiment.

If the fourteen terminals are provided, areas of all the connectionterminals 50 occupy about 47% of an area of the opening 90. Therefore,in the second embodiment, similar functions and effects to those in theabove-described first embodiment can be obtained.

In solder joining with laser, heat is less likely to escape around and atemperature is likely to increase at positions closer to a centralportion in a longitudinal direction of the tail connection end portion48 c while the heat is more likely to escape outside the connection endportion 48 c and the temperature is less likely to increase at positionscloser to end portions in the longitudinal direction. Because a portioncloser to an extended end side (distal end side) of the connection endportion 48 c is positioned closer to a center of an actuator block towhich the connection end portion 48 c is joined, the heat is likely toescape from the connection end portion 48 c to the actuator block atsuch portion.

Therefore, in the following embodiments, widths of connection terminals50 or intervals between the terminals are varied so that a temperatureof the connection end portion 48 c can be increased uniformly in solderjoining.

Third Embodiment

FIG. 11A is a schematic plan view of a tail connection end portion of aflexure according to the third embodiment. As shown in FIG. 11A,according to the third embodiment, intervals W1 between connectionterminals 50 positioned at opposite end portions in a longitudinaldirection of the connection end portion 48 c are set to be narrower thanan interval W2 between connection terminals 50 positioned at a centralportion in the longitudinal direction (W2>W1). Here, the intervals W1between the connection terminals 50 on opposite end sides are set to benarrower than intervals between the other connection terminals 50. In anexample, the interval W2 is about 0.15 mm and the intervals W1 are about0.08 mm.

The intervals between the terminals may be formed to gradually narrowfrom the connection terminals at the central portion toward theconnection terminals at the opposite end portions.

Fourth Embodiment

FIG. 11B is a schematic plan view of a tail connection end portion of aflexure according to a fourth embodiment. As shown in FIG. 11B,according to the fourth embodiment, only an interval W1 between twoconnection terminals 50 positioned at an extended end of the connectionend portion 48 c is formed to be narrower than intervals W2 betweenother connection terminals 50. Alternatively, the intervals between theconnection terminals 50 may be formed to gradually narrow from aproximal end side (suspension side) of the connection end portion 48 ctoward a distal end portion.

Fifth Embodiment

FIG. 12A is a schematic plan view of a tail connection end portion of aflexure according to a fifth embodiment. As shown in FIG. 12A, accordingto the fifth embodiment, widths WT2 of connection terminals 50positioned at opposite end portions in a longitudinal direction of theconnection end portion 48 c are set to be larger than widths WT1 ofconnection terminals 50 positioned at a central portion in thelongitudinal direction (WT2>WT1). Here, the widths WT2 of the connectionterminals 50 on opposite end sides are set to be larger than the widthsWT1 of the other connection terminals 50. In an example, the widths WT2are about 0.3 mm and the widths WT1 are about 0.2 mm.

The widths WT of the connection terminals 50 may be formed to graduallyincrease from the connection terminals 50 at the central portion towardthe connection terminals 50 at the opposite end portions.

Sixth Embodiment

FIG. 12B is a schematic plan view of a tail connection end portion of aflexure according to a sixth embodiment. As shown in FIG. 12B, accordingto the sixth embodiment, only a width WT2 of a connection terminal 50positioned at an extended end of the connection end portion 48 c isformed to be larger than widths WT1 of other connection terminals 50.Alternatively, the widths WT of the connection terminals 50 may beformed to gradually increase from a proximal end side (suspension side)of the connection end portion 48 c toward the extended end.

According to the above-described third to sixth embodiments, it ispossible to uniformly increase a temperature of the connection endportion 48 c in solder joining. In the embodiments, other structures ofthe connection end portion 48 c are similar to those of the connectionend portion 48 c in the above-described first embodiment. Therefore, inthe third to sixth embodiments, similar functions and effects to thosein the first embodiment can be obtained.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the inventions. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein may be made without departing from the spirit of theinventions. The accompanying claims and their equivalents are intendedto cover such forms or modifications as would fall within the scope andspirit of the inventions.

The number of the magnetic disks is not limited to five and may be fouror smaller or six or larger. The number of the suspension assemblies andthe number of the magnetic heads may be increased or decreased inaccordance with the number of the mounted magnetic disks. In theconnection end portion of each of the suspension assemblies, the shapes,the sizes, and the like of the connection terminals are not limited tothose in the above-described embodiments and can be changed in variousways as necessary. Kinds and functions of the connection terminals arenot limited to those in the above-described embodiments and can bechanged in various ways in accordance with functions of the magneticheads and the suspension assemblies.

What is claimed is:
 1. A suspension assembly comprising: a supportplate; a wiring member disposed on the support plate; and a headsupported on the support plate through the wiring member, wherein thewiring member comprises a distal end portion electrically connected tothe head, a connection end portion extending outside the support plate,and a plurality of wirings extending between the distal end portion andthe connection end portion, and the connection end portion includes anopening with predetermined length and width and thirteen or moreconnection terminals disposed in the opening and arranged at intervalsin a direction of the length, and a percentage of an area of the openingoccupied by a sum of areas of the thirteen or more connection terminalsis 40% to 65% inclusive.
 2. The suspension assembly of claim 1, whereinthe connection end portion comprises fourteen or more connectionterminals disposed in the opening and the sum of the areas of thefourteen or more connection terminals occupies 47% or more of the areaof the opening.
 3. The suspension assembly of claim 1, wherein thethirteen or more connection terminals include connection terminals for awrite head, connection terminals for a read head, connection terminalsfor an assisting element, connection terminals for a heater, connectionterminals for an HDI sensor, and connection terminals for amicro-actuator, the connection terminals for the HDI sensor or theconnection terminals for the heater are disposed between the connectionterminals for the assisting element and the connection terminals for theread head, and the connection terminals for the HDI sensor or theconnection terminals for the heater are disposed between the connectionterminals for the assisting element and the connection terminals for thewrite head.
 4. The suspension assembly of claim 1, wherein the thirteenor more connection terminals are arranged such that intervals betweenthe connection terminals positioned at one end portion in the directionof the length of the opening are narrower than intervals between theconnection terminals positioned at a central portion in the direction ofthe length of the opening.
 5. The suspension assembly of claim 1,wherein the thirteen or more connection terminals are arranged such thatintervals between the connection terminals positioned at one end portionin the direction of the length of the opening are narrower thanintervals between the other connection terminals.
 6. The suspensionassembly of claim 1, wherein a width of the connection terminalpositioned at an end portion in the direction of the length of theopening is larger than a width of the connection terminal positioned ata central portion in the direction of the length of the opening.
 7. Thesuspension assembly of claim 1, wherein a width of the connectionterminal positioned at one end portion in the direction of the length ofthe opening is larger than a width of the other connection terminals. 8.A disk device comprising: a disk-shaped recording medium; and thesuspension assembly of claim
 1. 9. The disk device of claim 8, whereinthe connection end portion comprises fourteen or more connectionterminals disposed in the opening and the sum of the areas of thefourteen or more connection terminals occupies 47% or more of the areaof the opening.
 10. The disk device of claim 8, wherein the thirteen ormore connection terminals include connection terminals for a write head,connection terminals for a read head, connection terminals for anassisting element, connection terminals for a heater, connectionterminals for an HDI sensor, and connection terminals for amicro-actuator, the connection terminals for the HDI sensor or theconnection terminals for the heater are disposed between the connectionterminals for the assisting element and the connection terminals for theread head, and the connection terminals for the HDI sensor or theconnection terminals for the heater are disposed between the connectionterminals for the assisting element and the connection terminals for thewrite head.
 11. The disk device of claim 8, wherein the thirteen or moreconnection terminals are arranged such that intervals between theconnection terminals positioned at one end portion in the direction ofthe length of the opening are narrower than intervals between theconnection terminals positioned at a central portion in the direction ofthe length of the opening.
 12. The disk device of claim 8, wherein thethirteen or more connection terminals are arranged such that intervalsbetween the connection terminals positioned at one end portion in thedirection of the length of the opening are narrower than intervalsbetween the other connection terminals.
 13. The disk device of claim 8,wherein a width of the connection terminal positioned at an end portionin the direction of the length of the opening is larger than a width ofthe connection terminal positioned at a central portion in the directionof the length of the opening.
 14. The disk device of claim 8, wherein awidth of the connection terminal positioned at one end portion in thedirection of the length of the opening is larger than a width of theother connection terminals.